JPBC ing： 留言板之一：用JAVABEAN與DAO封裝數據的業務邏輯及操作

??????首先，先用DAO把數據業務邏輯部分分離開來，因為我只用到MySQL，所以就省略了工廠類，定了一個業務邏輯的接口及實現它的類。

?????MessageDAO.java??????

package?DAO.iface;

import?java.util.List;
/**?*//**
?*?進行數據操作的業務邏輯類接口的DAO
?*?@author?Administrator
?*
?*/
public?interface?MessageDAO?{
????public?List?getMessageList();
}

???MessageDAOMySQL.java

package?DAO.impl;

import?java.sql.Connection;
import?java.sql.ResultSet;
import?java.sql.SQLException;
import?java.sql.Statement;
import?java.util.ArrayList;
import?java.util.List;

import?bean.DatabaseBean;
import?bean.MessageBoardBean;

import?DAO.iface.MessageDAO;
/**?*//**
?*?進行數據操作的業務邏輯類
?*?@author?Administrator
?*
?*/
public?class?MessageDAOMySQL?implements?MessageDAO?{
????private?DatabaseBean?db?=?null;
????private?Connection?conn?=?null;
????private?Statement?stmt?=?null;
????private?ResultSet?rs?=?null;
????private?List<MessageBoardBean>?messageList;

????public?MessageDAOMySQL()?{
????????db?=?new?DatabaseBean();
????}

????public?List?getMessageList()?{
????????????messageList?=?new?ArrayList<MessageBoardBean>();
????????????conn?=?db.getConn();
????????????stmt?=?db.getStatement(conn);
????????????rs?=?db.getResultSet(stmt,?"select?*?from?messageboard;");
????????????try?{
????????????????while?(rs.next())?{
????????????????????MessageBoardBean?tempMessage?=?new?MessageBoardBean();
????????????????????tempMessage.setUserName(rs.getString(2));
????????????????????tempMessage.setTitle(rs.getString(3));
????????????????????tempMessage.setWords(rs.getString(4));
????????????????????tempMessage.setTime(rs.getString(5));
????????????????????messageList.add(tempMessage);
????????????????}
????????????}?catch?(SQLException?e)?{
????????????????e.printStackTrace();
????????????}?finally?{
????????????????db.close(rs);
????????????????db.close(stmt);
????????????????db.close(conn);
????????????}
????????????return?messageList;
????}

}

??????為了對外擴展可能在此用到數據庫的操作，所以將數據庫的連接和簡單的增刪改查等操作封裝到一個Bean中。

???DatabaseBean.java
???

package?bean;

import?java.sql.Connection;
import?java.sql.DriverManager;
import?java.sql.ResultSet;
import?java.sql.SQLException;
import?java.sql.Statement;


public?class?DatabaseBean?{

????/**?*//**
?????*?數據庫的封裝，javaBean
?????*?@param?nonels
?????*/
????public??Connection?getConn()?{
????????Connection?conn?=?null;
????????try?{
????????????Class.forName("com.mysql.jdbc.Driver");
????????????conn?=?DriverManager.getConnection("jdbc:mysql://localhost/JPBC?user=root&password=root");
????????}?catch?(ClassNotFoundException?e)?{
????????????e.printStackTrace();
????????}?catch?(SQLException?e)?{
????????????e.printStackTrace();
????????}
????????return?conn;
????}
????
????public??Statement?getStatement(Connection?conn)?{
????????Statement?stmt?=?null;
????????try?{
????????????if(conn?!=?null)?{
????????????????stmt?=?conn.createStatement();
????????????}?
????????}?catch?(SQLException?e)?{
????????????e.printStackTrace();
????????}
????????return?stmt;
????}
????
????public??ResultSet?getResultSet(Statement?stmt,?String?sql)?{
????????ResultSet?rs?=?null;
????????try?{
????????????if(stmt?!=?null)?{
????????????????rs?=?stmt.executeQuery(sql);
????????????}
????????}?catch?(SQLException?e)?{
????????????e.printStackTrace();
????????}
????????return?rs;
????}
????
????public??void?close(Connection?conn)?{
????????try?{
????????????if(conn?!=?null)?{
????????????????conn.close();
????????????????conn?=?null;
????????????}
????????}?catch?(SQLException?e)?{
????????????e.printStackTrace();
????????}
????}
????
????public??void?close(Statement?stmt)?{
????????try?{
????????????if(stmt?!=?null)?{
????????????????stmt.close();
????????????????stmt?=?null;
????????????}
????????}?catch?(SQLException?e)?{
????????????e.printStackTrace();
????????}
????}
????
????public??void?close(ResultSet?rs)?{
????????try?{
????????????if(rs?!=?null)?{
????????????????rs.close();
????????????????rs?=?null;
????????????}
????????}?catch?(SQLException?e)?{
????????????e.printStackTrace();
????????}
????}

}

??????再將留言板的各個信息也封裝成一個Bean

??????MeassageBoardBean.java
??????

package?bean;
/**?*//**
?*??留言板信息的bean
?*?@author?nonles
?*
?*/

public?class?MessageBoardBean?{
????private?String?userName;
????private?String?title;
????private?String?words;
????private?String?time;
????
????public?MessageBoardBean()?{
????????
????}
????
????public?String?getTime()?{
????????return?time;
????}
????public?void?setTime(String?time)?{
????????this.time?=?time;
????}
????public?String?getTitle()?{
????????return?title;
????}
????public?void?setTitle(String?title)?{
????????this.title?=?title;
????}
????public?String?getUserName()?{
????????return?userName;
????}
????public?void?setUserName(String?userName)?{
????????this.userName?=?userName;
????}
????public?String?getWords()?{
????????return?words;
????}
????public?void?setWords(String?words)?{
????????this.words?=?words;
????}
????
}

posted on 2008-10-16 23:45 nonels 閱讀(808) 評論(1)  編輯  收藏 所屬分類: J2EE

評論

# re: JPBC ing： 留言板之一：用JAVABEAN與DAO封裝數據的業務邏輯及操作 2012-12-10 09:26 黑色紀念館

能具體解釋一下每行代碼的意思嗎，非常感謝  回復  更多評論   

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